Assessment of hydrogeochemical status of groundwater in a coastal region of Southeast coast of India

S Chidambaram,C Thivya,M V Prasanna,M Nepolian,K Srinivasamoorthy,J Sarathidasan,R Thilagavathi,C Singaraja

doi:10.1007/s13201-018-0649-2

Abstract

A study was conducted in a coastal region of Cuddalore district of Tamil Nadu, India, to identify the hydrogeochemical processes controlling the groundwater chemistry. The major geological units of the study area are sandstone, clay, alluvium, and laterite soils of Tertiary and Quaternary age. A total of 64 groundwater samples were measured for major ions and stable isotopes. Higher electrical conductivity values indicate the poor quality groundwater along the coastal region. Saline water intrusion mainly affects the hydrochemical composition of the aquifer water reflected by Na–Cl-type waters. Cl−/(Cl− + HCO3−) ratio also indicates the mixing of fresh groundwater with saline water. The results of δD and δ18O analyses show that isotopic compositions of groundwater ranges from − 7.7 to − 2.1‰ for δ18O and from − 55.6 to − 18.5‰ for δD. Correlation and factor analysis were carried out to find the association of ions and to determine the major factors controlling the groundwater chemistry of the region. The study indicates that ion exchange, weathering, salt water intrusion along the coast, and anthropogenic impacts are the major controlling factors for the groundwater chemistry of the region.

Highlights

IntroductionThe quality of coastal aquifers is controlled by the variations of hydrogeochemical processes like salt water intrusion, geogenic process (weathering, ion exchange and rock-water interaction), and anthropogenic activities (agriculture, industry and urbanization)
The quality of coastal aquifers is controlled by the variations of hydrogeochemical processes like salt water intrusion, geogenic process, and anthropogenic activities
Mg, Cl, and HCO3 were measured by titration and SO4, NO3, PO4, and H4SiO4 were obtained by using Digital Spectrophotometer (ModelGS5 700A)

Summary

Introduction

The quality of coastal aquifers is controlled by the variations of hydrogeochemical processes like salt water intrusion, geogenic process (weathering, ion exchange and rock-water interaction), and anthropogenic activities (agriculture, industry and urbanization). Every part of the country has its own causative factors for the variation of groundwater quality. Many researchers have stated that rapid urbanization along the coastline aquifers openly or secondarily affects the groundwater quality and quantity (Boukari et al 1996; Lambrakis 1998; Zilberbrand et al 2001; Foppen 2002; Faye et al 2004). It is important to understand how water–rock interaction (weathering) or any type of anthropogenic impact affects groundwater quality (Todd 1980; Kelley 1940).

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Conclusion